953 resultados para Elongation at break


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Purpose: The genetics events occurring in the development of mucoepidermoid carcinoma of the conjunctiva have not been extensively investigated. A t(11;19)(q21;p13) translocation has been reported in more than 50% of mucoepidermoid carcinoma of the salivary glands. This translocation induces a chimeric MECT1-MAML2 protein that act as a transcription activation factor in CREB and Notch pathways. Sustained expression of MECT1-MALM2 in RKE3 cells was tumorigenic in a mouse model. The presence of this translocation has been correlated with a better prognosis in mucoepidermoid carcinoma of the salivary glands. The purpose of this study was to identify the presence or absence of this translocation in mucoepidermoid carcinoma of the conjunctiva.Methods: We retrospectively reviewed all conjunctival mucoepidermoid carcinoma cases from the pathological files of Jules Gonin Eye Hospital from 1960-2010. The relevant clinico-pathological data was obtained. The presence of the t(11;19)(q21;p13) translocation was investigated by FISH using a dual color break apart probe. 100 nuclei were evaluated in each case. Normal conjunctiva was included as a control.Results: Material for FISH analysis was available in 9 patients (11 tumors). There were 2 females and 7 males. The mean age was years 71, 4 years old. Tumors were involving the bulbar conjunctiva in 6 cases and the tarsal conjunctiva in 5 cases. In a young patient of 30 years old, mucoepidermoid carcinoma was developed in the context of Xeroderma Pigmentosum. Hybridization could successfully be performed in 8 patients (9 tumors). No disruption of the dual color fusion signal was observed in all the cases, suggesting an absence of t(11;19)(q21;p13) translocation in mucoepidermoid carcinoma of the conjunctiva.Conclusions: Although our study encompasses only a limited number of cases due to the rarity of mucoepidermoid carcinoma of the conjunctiva, it demonstrates that a translocation commonly found in this tumor at other locations is not identified in the conjunctiva, suggesting that different mechanisms occur in the development of these tumors.

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Convective flows of a small Prandtl number fluid contained in a two-dimensional cavity subject to a lateral thermal gradient are numerically studied by using different techniques. The aspect ratio (length to height) is kept at around 2. This value is found optimal to make the flow most unstable while keeping the basic single-roll structure. Two cases of thermal boundary conditions on the horizontal plates are considered: perfectly conducting and adiabatic. For increasing Rayleigh numbers we find a transition from steady flow to periodic oscillations through a supercritical Hopf bifurcation that maintains the centrosymmetry of the basic circulation. For a Rayleigh number of about ten times that of the Hopf bifurcation the system initiates a complex scenario of bifurcations. In the conductive case these include a quasiperiodic route to chaos. In the adiabatic one the dynamics is dominated by the interaction of two Neimark-Sacker bifurcations of the basic periodic solutions, leading to the stable coexistence of three incommensurate frequencies, and finally to chaos. In all cases, the complex time-dependent behavior does not break the basic, single-roll structure.

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The issue of de Sitter invariance for a massless minimally coupled scalar field is examined. Formally, it is possible to construct a de Sitterinvariant state for this case provided that the zero mode of the field is quantized properly. Here we take the point of view that this state is physically acceptable, in the sense that physical observables can be computed and have a reasonable interpretation. In particular, we use this vacuum to derive a new result: that the squared difference between the field at two points along a geodesic observers spacetime path grows linearly with the observers proper time for a quantum state that does not break de Sitter invariance. Also, we use the Hadamard formalism to compute the renormalized expectation value of the energy-momentum tensor, both in the O(4)-invariant states introduced by Allen and Follaci, and in the de Sitterinvariant vacuum. We find that the vacuum energy density in the O(4)-invariant case is larger than in the de Sitterinvariant case.

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Contexte: L'intervention "Break The Chains" 2012 de l'OFSP a l'intention des gays visait à informer sur la primo-infection et a inciter a un test de dépistage VIH. Design: L'évaluation a recouru a un design Pre-Post avec 2 dispositifs: A) enquête par questionnaire Internet avec une vague avant la campagne et une après (transversal repete); B) 1) relevé centré sur le canton de Zurich du nombre de test effectues par des gays durant le premier semestre 2012 utilisant des données récoltées par Sentinella, par les centres de test utilisant l'application BerDa et auprès des praticiens de HIV-Prakt; et 2) recueil d'information par le questionnaire internet post-intervention des intentions d'effectuer un test VIH. Résultats: 366 HSH ont répondu au questionnaire de la phase pré-, et 964 à la phase post-intervention. 69.8% ont entendu parler de la campagne. Parmi les répondants ayant identifie le message, 48.6% se sont sentis concernes. Avant la campagne, 34.2% des répondants identifiaient les 4 symptômes de la primo-infection, 46.4% se sentaient bien informes et 79.2% connaissaient le délai minimum pour qu'un test informe sur une absence d'infection; après la campagne, ces proportions étaient 39.6%, 62.0% et 85.2%. 17.1% des répondants ont déclaré avoir fait/avoir l'intention de faire, un test VIH suite à la campagne. Le nombre de tests effectues par les répondants Internet montre effectivement un pic dans le 2e trimestre 2012; les données BerDa montrent une stabilité du nombre total de tests. Les données épidémiologiques montrent une augmentation de la proportion et du nombre d'infections récentes détectées durant ce 2e trimestre, mais une diminution des infections anciennes. Conclusions: L'intervention BTC a amélioré légèrement les connaissances relatives à la phase de primo-infection du VIH et a la nécessité d'effectuer un test VIH. Elle semble avoir incite le public cible à effectuer un test VIH qui n'aurait pas été réalisé autrement et a peut-être ainsi contribuer a la détection d'infections récentes.

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Tat activates transcription by interacting with Sp1, NF-kappaB, positive transcription elongation factor b, and trans-activator-responsive element (TAR). Tat and Sp1 play major roles in transcription by protein-protein interactions at human immunodeficiency virus, type 1 (HIV-1) long terminal repeat. Sp1 activates transcription by interacting with cyclin T1 in the absence of Tat. To disrupt the transcription activation by Tat and Sp1, we fused Sp1-inhibiting polypeptides, zinc finger polypeptide, and the TAR-binding mutant Tat (TatdMt) together. A designed or natural zinc finger and Tat mutant fusion was used to target the fusion to the key regulatory sites (GC box and TAR) on the long terminal repeat and nascent short transcripts to disrupt the molecular interaction that normally result in robust transcription. The designed zinc finger and TatdMt fusions were targeted to the TAR, and they potently repressed both transcription and replication of HIV-1. The Sp1-inhibiting POZ domain, TatdMt, and zinc fingers are key functional domains important in repression of transcription and replication. The designed artificial zinc fingers were targeted to the high affinity Sp1-binding site, and by being fused with TatdMt and POZ domain, they strongly block both Sp1-cyclin T1-dependent transcription and Tat-dependent transcription, even in the presence of excess expressed Tat.

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It is well known that radiative corrections evaluated in nontrivial backgrounds lead to effective dispersion relations which are not Lorentz invariant. Since gravitational interactions increase with energy, gravity-induced radiative corrections could be relevant for the trans-Planckian problem. As a first step to explore this possibility, we compute the one-loop radiative corrections to the self-energy of a scalar particle propagating in a thermal bath of gravitons in Minkowski spacetime. We obtain terms which originate from the thermal bath and which indeed break the Lorentz invariance that possessed the propagator in the vacuum. Rather unexpectedly, however, the terms which break Lorentz invariance vanish in the high three-momentum limit. We also found that the imaginary part, which gives the rate of approach to thermal equilibrium, vanishes at one loop.

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We present a simple model of communication in networks with hierarchical branching. We analyze the behavior of the model from the viewpoint of critical systems under different situations. For certain values of the parameters, a continuous phase transition between a sparse and a congested regime is observed and accurately described by an order parameter and the power spectra. At the critical point the behavior of the model is totally independent of the number of hierarchical levels. Also scaling properties are observed when the size of the system varies. The presence of noise in the communication is shown to break the transition. The analytical results are a useful guide to forecasting the main features of real networks.

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ABSTRACT Knowledge of the terms (or processes) of the soil water balance equation or simply the components of the soil water balance over the cycle of an agricultural crop is essential for soil and water management. Thus, the aim of this study was to analyze these components in a Cambissolo Háplico (Haplocambids) growing muskmelon (Cucumis melo L.) under drip irrigation, with covered and uncovered soil, in the municipality of Baraúna, State of Rio Grande do Norte, Brazil (05º 04’ 48” S, 37º 37’ 00” W). Muskmelon, variety AF-646, was cultivated in a flat experimental area (20 × 50 m). The crop was spaced at 2.00 m between rows and 0.35 m between plants, in a total of ten 50-m-long plant rows. At points corresponding to ⅓ and ⅔ of each plant row, four tensiometers (at a distance of 0.1 m from each other) were set up at the depths of 0.1, 0.2, 0.3, and 0.4 m, adjacent to the irrigation line (0.1 m from the plant row), between two selected plants. Five random plant rows were mulched using dry leaves of banana (Musa sp.) along the drip line, forming a 0.5-m-wide strip, which covered an area of 25 m2 per of plant row with covered soil. In the other five rows, there was no covering. Thus, the experiment consisted of two treatments, with 10 replicates, in four phenological stages: initial (7-22 DAS - days after sowing), growing (22-40 DAS), fruiting (40-58 DAS) and maturation (58-70 DAS). Rainfall was measured with a rain gauge and water storage was estimated by the trapezoidal method, based on tensiometer readings and soil water retention curves. For soil water flux densities at 0.3 m, the tensiometers at the depths of 0.2, 0.3, and 0.4 m were considered; the tensiometer at 0.3 m was used to estimate soil water content from the soil water retention curve at this depth, and the other two to calculate the total potential gradient. Flux densities were calculated through use of the Darcy-Buckingham equation, with hydraulic conductivity determined by the instantaneous profile method. Crop actual evapotranspiration was calculated as the unknown of the soil water balance equation. The soil water balance method is effective in estimating the actual evapotranspiration of irrigated muskmelon; there was no significant effect of soil coverage on capillary rise, internal drainage, crop actual evapotranspiration, and muskmelon yield compared with the uncovered soil; the transport of water caused by evaporation in the uncovered soil was controlled by the break in capillarity at the soil-atmosphere interface, which caused similar water dynamics for both management practices applied.

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PURPOSE: To compare clinical benefit response (CBR) and quality of life (QOL) in patients receiving gemcitabine (Gem) plus capecitabine (Cap) versus single-agent Gem for advanced/metastatic pancreatic cancer. PATIENTS AND METHODS: Patients were randomly assigned to receive GemCap (oral Cap 650 mg/m(2) twice daily on days 1 through 14 plus Gem 1,000 mg/m(2) in a 30-minute infusion on days 1 and 8 every 3 weeks) or Gem (1,000 mg/m(2) in a 30-minute infusion weekly for 7 weeks, followed by a 1-week break, and then weekly for 3 weeks every 4 weeks) for 24 weeks or until progression. CBR criteria and QOL indicators were assessed over this period. CBR was defined as improvement from baseline for >or= 4 consecutive weeks in pain (pain intensity or analgesic consumption) and Karnofsky performance status, stability in one but improvement in the other, or stability in pain and performance status but improvement in weight. RESULTS: Of 319 patients, 19% treated with GemCap and 20% treated with Gem experienced a CBR, with a median duration of 9.5 and 6.5 weeks, respectively (P < .02); 54% of patients treated with GemCap and 60% treated with Gem had no CBR (remaining patients were not assessable). There was no treatment difference in QOL (n = 311). QOL indicators were improving under chemotherapy (P < .05). These changes differed by the time to failure, with a worsening 1 to 2 months before treatment failure (all P < .05). CONCLUSION: There is no indication of a difference in CBR or QOL between GemCap and Gem. Regardless of their initial condition, some patients experience an improvement in QOL on chemotherapy, followed by a worsening before treatment failure.

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We investigate the collective organization of paramagnetic colloidal particles externally driven above the periodic stripes of a uniaxial ferrimagnetic garnet film. An external field modulation induces vibration of the stripe walls and produces random motion of the particles. Defects in the stripe pattern break the symmetry of the potential and favor particle nucleation into large clusters above a critical density. Mismatch between particle size and pattern wavelength generates assemblies with different morphological order. At even higher field strengths, repulsive dipolar interactions between the particles induce cluster melting. We propose a novel approach to generate and externally control a variety of colloidal assemblies.

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Fall enrollment grew 1.2 percent to a record high of 88,104 unduplicated students in fiscal year 2009 (Table 1). College enrollment has grown for 11 consecutive years since enrollment slipped in fiscal year 1997. In the 44‐year history of the modern community college system, enrollment has only fallen four times (Figure 1). Enrollment growth was slightly slower than prior years. In 2006, enrollment grew over three percent, while enrollment grew 2.5 percent last year. Nevertheless, enrollment growth is outpacing the projected nationwide growth in community colleges (Hussar and Bailey, 2008: Table 16). For the second consecutive year, part‐time enrollment exceeded full‐time enrollment. Slightly over half, 50.9 percent, of students are enrolled in less than 12 credit hours. Last year, part‐time enrollment exceeded full‐time enrollment for the first time. The shift represents growing enrollment by working students and joint enrollment— high school students who enroll in community colleges.. Nationally, part‐time enrollment at public two‐year colleges has exceeded full‐time enrollment for more than 15 years. In 2006, part‐time students exceeded full‐time students by 60 percent (Hussar and Bailey, 2008: Table 16). Iowa’s enrollment growth has traditionally been consistent. Enrollment decreased four times—1976, 1983, 1984, and 1997—during the entire 44‐year history. Fulltime enrollment decreased nine times over the same period while part time enrollment only fell twice. The remainder of this report will break down credit enrollment by credit hours, student demographics, the programs in which students are enrolled, how the programs break down demographically, and joint enrollment.

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A high-resolution U-Pb zircon geochronological study of plutonic units along the south Peruvian margin between 17 degrees and 18 degrees S allows the integration of the geochemical, geodynamic and tectonic evolution of this part of the Andean margin. This study focuses on the composite Jurassic-early Cretaceous Ilo Batholith that was emplaced along the southern Peruvian coast during two episodes of intrusive magmatism; a first period between 173 and 152 Ma (with a peak in magmatic activity between roughly 168 and 162 Ma) and a second period between 110 and 106 Ma. Emplacement of the Jurassic part of the composite Ilo Batholith shortly post-dated the accumulation of the volcanosedimentary succession it intruded (Chocolate formation), which allows to estimate a subsidence rate for this unit of similar to 3.5 km/Ma. The emplacement of the main peak of Jurassic plutonism of the Ilo Batholith was also closely coeval with widespread and repeated slumping (during deposition of the Cachios Formation) in the back-arc region, suggesting a common causal link between these phenomena, which is discussed in the context of an observed 100 km trenchward arc migration at similar to 175 Ma, and the relation with extensional tectonics that prevailed along the Central Andean margin during Pangaea break-up. (C) 2012 Elsevier B.V. All rights reserved.

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Plants compete with neighbouring vegetation for limited resources. In competition for light, plants adjust their architecture to bring the leaves higher in the vegetation where more light is available than in the lower strata. These architectural responses include accelerated elongation of the hypocotyl, internodes and petioles, upward leaf movement (hyponasty), and reduced shoot branching and are collectively referred to as the shade avoidance syndrome. This review discusses various cues that plants use to detect the presence and proximity of neighbouring competitors and respond to with the shade avoidance syndrome. These cues include light quality and quantity signals, mechanical stimulation, and plant-emitted volatile chemicals. We will outline current knowledge about each of these signals individually and discuss their possible interactions. In conclusion, we will make a case for a whole-plant, ecophysiology approach to identify the relative importance of the various neighbour detection cues and their possible interactions in determining plant performance during competition.

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Cooperation in joint enterprises can easily break down when self-interests are in conflict with collective benefits, causing a tragedy of the commons. In such social dilemmas, the possibility for contributors to invest in a common pool-rewards fund, which will be shared exclusively among contributors, can be powerful for averting the tragedy, as long as the second-order dilemma (i.e. withdrawing contribution to reward funds) can be overcome (e.g. with second-order sanctions). However, the present paper reveals the vulnerability of such pool-rewarding mechanisms to the presence of reward funds raised by defectors and shared among them (i.e. anti-social rewarding), as it causes a cooperation breakdown, even when second-order sanctions are possible. I demonstrate that escaping this social trap requires the additional condition that coalitions of defectors fare poorly compared with pro-socials, with either (i) better rewarding abilities for the latter or (ii) reward funds that are contingent upon the public good produced beforehand, allowing groups of contributors to invest more in reward funds than groups of defectors. These results suggest that the establishment of cooperation through a collective positive incentive mechanism is highly vulnerable to anti-social rewarding and requires additional countermeasures to act in combination with second-order sanctions.